AWUS01 KWNH 291316
FFGMPD
NCZ000-SCZ000-291800-

Mesoscale Precipitation Discussion 1140
NWS Weather Prediction Center College Park MD
915 AM EDT Sat Aug 29 2026

Areas affected...Eastern North Carolina & Coastal South Carolina

Concerning...Heavy rainfall...Flash flooding possible

Valid 291314Z - 291800Z

Summary...Showers and thunderstorms will move slowly along the
coast and near a stationary front through the early afternoon.
Rainfall rates in excess of 2"/hr will result in axes of 2-4" of
rain with locally higher amounts. This may cause flash flooding.

Discussion...The regional radar mosaic this morning shows
persistent moderate rain with embedded convective elements aligned
to the North Carolina/South Carolina coasts. This activity is
developing just ahead of a surface stationary front analyzed by
WPC, with additional convective development occurring along the
front itself, as well as a weakening trough/land breeze boundary.
PWs this morning as measured via regional UA soundings were above
the 90th percentile (2.28" at KMHX, 2.31" at CHS) with saturated
adiabatic lapse rates noted through the entire column depth.
Freezing levels as high as 14,000 ft are supporting warm rain
processes, and this is resulting in hourly rainfall measured via
MRMS as high as 2.5" in the strongest convective cores.

The HRRR is struggling to resolve the current activity this
morning, but the RRFS and 3kmNAM are initializing better and in
agreement that activity will continue to expand/intensify for the
next several hours. This will be driven by MLCAPE spreading inland
from the coast coincident with synoptic ascent within the
favorably placed RRQ of an upper jet streak. While the RAP
suggests there will be some impressive CINH across the Pee Dee
region, otherwise the coasts of NC/SC and much of eastern NC will
support rainfall rates for which the HREF suggests has a 20-40%
chance of exceeding 2"/hr. Mean 0-6km winds of just 5-10 kts (less
along the stationary front where storms may feature nearly 0 net
motion for a while) aligned to the boundary should allow for
training/backbuilding, leading to rainfall of 2-4" with locally
higher amounts (10-30% for 5+".

FFG across this region is naturally elevated at 3-4"/3hrs, but
7-day rainfall across parts of the area has been above 300% of
normal leading to somewhat more vulnerable soils. The HREF and
REFS both suggest around a 30-40% chance of FFG exceedance in a
few areas, especially between the Crystal Coast, Downeast NC, and
the Tidewater Region. While in general there appears to be only an
isolated risk for flash flooding through the afternoon, it is this
area that appears to have the greatest risk for impacts.


Weiss

ATTN...WFO...AKQ...CHS...ILM...MHX...RAH...

ATTN...RFC...ALR...NWC...

LAT...LON   36387695 36217604 36107570 35637537 35187544 
            34717619 34297706 33677807 33077904 32707983 
            32768003 33218003 33587957 34027923 34567936 
            34837953 35127980 35577988 35827961 36037895 
            36307788 

$$
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